Problem: Solve for $x$ : $3\sqrt{x} - 10 = 6\sqrt{x} + 7$
Answer: Subtract $3\sqrt{x}$ from both sides: $(3\sqrt{x} - 10) - 3\sqrt{x} = (6\sqrt{x} + 7) - 3\sqrt{x}$ $-10 = 3\sqrt{x} + 7$ Subtract $7$ from both sides: $-10 - 7 = (3\sqrt{x} + 7) - 7$ $-17 = 3\sqrt{x}$ Divide both sides by $3$ $\frac{-17}{3} = \frac{3\sqrt{x}}{3}$ Simplify. $-\dfrac{17}{3} = \sqrt{x}$ The principal root of a number cannot be negative. So, there is no solution.